ABSTRACT Pre-exposure prophylaxis (PrEP) is a promising tool for the prevention of HIV acquisition during pregnancy and the postpartum period and is a recommended component of a comprehensive package of prevention of mother- to-child HIV transmission services. Yet, few strategies exist to promote person-centered shared decision-making about PrEP use during pregnancy and breastfeeding despite the complexity of this decision and the importance of shared decision-making for medication adherence. The proposed training and research plan in this Mentored Research Scientist Development Award (K01) application will provide the essential training and skills that the principle investigator, Dr. Lauren M. Hill, PhD, needs to launch a productive career in PrEP decision-making research and in the development and evaluation of behavioral interventions to promote the utilization of and adherence to medicines for the prevention and treatment of HIV. Further, the research conducted throughout the course of this award would contribute meaningfully to the successful delivery of PrEP in the context of antenatal care in sub-Saharan Africa to ensure that decision-making regarding PrEP use by pregnant and breastfeeding women is person-centered to encourage appropriate and adherent use. To achieve this, Dr. Hill proposes three aims: First, she will identify values important to women?s decision-making about PrEP use during pregnancy and breastfeeding through a mixed methods formative study. Second, using this information and the results of a comprehensive needs assessment with pregnant women, their partners, and antenatal health care workers, she will develop a PrEP shared decision-making aid. Third, she will conduct a pilot trial to evaluate the effect of the shared decision-making intervention on the proximal cognitive endpoint of decisional conflict and explore the treatment effect on PrEP adherence. The training acquired by Dr. Hill through this timely study, in combination with didactic coursework, applied training, and mentorship will target the four training objectives: 1) to build expertise in medical decision-making with a focus on the development and evaluation of shared decision- making interventions; 2) to gain training in methods for the design, management, and analysis of trials to evaluate clinical interventions supporting the use of biomedical HIV prevention methods; 3) to master skills in the design of mixed methods studies and integration of mixed methods data for intervention design and evaluation; and 4) to develop the professional skills, expertise, and pilot data to facilitate her development toward research independence. Dr. Hill proposes to achieve these goals through a rigorous program of training and research to build upon and complement her training and experience in behavioral research for the primary prevention of HIV to fully prepare her for a career as an independent scientist in the field of global HIV/AIDS prevention.